In military and police firearms applications almost all of the ammunition consumed is used for training. For some training purposes, however, normal ammunition is not adequate. An alternative type of known training ammunition, represented by U.S. Pat. No. 5,359,937 (adopted herein by reference), fires a low-mass projectile relying on a special, low-energy cartridge designed to provide cycling of suitably-modified, recoil-operated automatic weapons.
An advantage of the low-energy training ammunition is that it has a shorter range and lower penetration capacity than standard ammunition. This permits use of smaller, less secure firing ranges as training facilities. If standard ammunition were accidentally employed in these facilities, unexpected dangers would arise from the increased striking power and range of such standard ammunition.
The weapon modifications required to permit cycling while firing low-energy training ammunition generally include replacing or modifying the barrel, and sometimes replacing or adding certain other components, depending on the weapon involved. These modifications also take safety into consideration. For example, in 9 mm automatic firearms, the caliber of the substitute barrel may be smaller than the diameter of the projectiles in standard 9 mm ammunition. If an attempt is made to chamber a standard round in such a training-adapted firearm, the design of the chamber and barrel will not normally permit entry of the standard projectile. This ensures that such modified weapons cannot fire standard, live ammunition.
Firearms of other calibers, such as caliber 0.45, may also be converted to fire the same low-energy training ammunition using similar training barrels as for converted 9 mm pistols.
The low-energy cartridge represented by U.S. Pat. No. 5,359,937, in combination with a substitute training barrel, provides recoil actuated cartridge case ejection through a pure blow-back action. Such a system, when firing appropriate marking cartridges, makes an effective close-range, force-on-force training system. Hits, which are on-lethal, are denoted by red, blue or other coloured marks. his system enhances the realism and training value of interactive scenario tactical training because it allows trainees to use their service weapons in a representative manner in exercises simulating, for example, counter-terrorism, close quarters combat, urban fighting, protection of dignitaries, trench clearing, and fighting in wooded areas.
When firing standard ammunition, with its abundant associated energy, it is necessary in many weapons, particularly handguns, to lock the barrel to the slide during the beginning of their rearward motion for a period long enough for the projectile to exit the barrel muzzle while the breech is still closed. This allows the chamber pressure to drop before the breech opens to eject the spent cartridge case. A locking mechanism couples the slide and barrel together for the first portion of the recoil, and then releases the slide. Thus, in such normal weapons, the barrel recoils, at least partially, with the slide. Upon unlocking, the slide continues its rearward travel while the barrel stops in the proper position to receive the next round from the magazine to be chambered.
In a training barrel it is necessary to omit this barrel-locking mechanism and, by so doing, the recoil action becomes pure blow-back of the slide only. This must be done because there is not enough energy in low-energy training cartridges to precipitate sufficient recoil to carry the barrel and the slide rearwardly in their standard configurations. A training barrel of the type addressed by this invention is similar in most aspects to the standard barrel for a particular pistol which normally relies on a barrel locking mechanism, but is modified, in part, by removing this locking mechanism, so that the barrel and the slide are no longer held together for the first portion of the recoil cycle.
In some converted pistols, however, after the barrel-locking mechanism has been removed so that the weapon can fire low-energy ammunition, as represented by U.S. Pat. No. 5,359,937, the barrel does not move rearward far enough, if at all, after firing to be in its normal position to receive the next round to be chambered. This happens precisely because the barrel is no longer locked to the slide, which would normally carry the barrel to the correct position before unlocking and leaving it there.
It is, therefore, an objective of this invention to provide a conversion barrel system for this class of firearm that will contribute to the proper positioning of the barrel for chambering.
A way to do this for certain 9 mm pistols, such as the Walther P-5, has been described in PCT Patent Application PCT/CA/00174 dated Mar. 14, 1997 and conceived by the same inventor as herein. The contents of this application, which designates the United States of America, are adopted herein by reference. This PCT application provides a system for the positioning of the barrel for chambering by adding a spring-loaded device to the bottom of the training barrel which, upon firing of the weapon, positively moves the barrel rearward to its required position for receiving the next cartridge from the magazine in a manner which is completely independent from the motion of the slide. The present invention does the same thing in part, but in a different mechanical configuration.
Even if the barrel were carried to its most rearward position, which is most favourable for chambering of the next cartridge, trouble-free chambering is not assured because the motion dynamics of the low-energy training cartridge as it leaves the magazine and enters the chamber are not the same as those of a service cartridge. This is due to the much lower weight of the training cartridge with its paucity of propellant and thin-walled plastic training projectile.
There is also a difference in weight distribution, which means that the center of gravity of the low-energy training cartridge is shifted rearwards compared to standard service cartridges with their greater amount of propellant and heavier metal projectiles. In addition, the external shape of the low-energy cartridge is not identical to that of service cartridges, and this too contributes to differences in the chambering process. The training cartridge may, therefore, require additional guidance as it moves from the magazine to the chamber to ensure that it does not jam during this high-speed transfer involving both vertical and horizontal movement. The invention herein, in one variant, addresses this consideration as well by providing a removable feed ramp extension to the end of the training barrel. The ramp must be removable with respect to the training barrel because it is not possible to insert it integrally with the training barrel without modifying the slide and/or the frame. Such modifications are not acceptable because the weapon must be capable of being reconverted back to the firing of service ammunition by simply removing the training barrel and reinserting the service barrel.
A second objective of the invention, therefore, is to provide a supplementary, moveable feed ramp between the magazine and the entrance to the chamber that will greatly increase the probability of proper chambering of the next low-energy training cartridge to be fired.
A way to do this for certain 9 mm pistols, such as the Sig 225, has been described in U.S. patent application Ser. No. 08/863,078, dated May 23, 1997, as conceived by the same inventor and adopted herein by reference. This application describes a system for ensuring proper chambering of low-energy training ammunition, as represented by U.S. Pat. No. 5,359,937, by fitting a removable ramp extension to the chamber end of a Sig 225 training barrel, such extension extending rearward towards the top of the magazine in such a fashion as to allow smooth passage from the magazine to the chamber of the next round to be fired. The present invention does the same thing in part, but by means of a different mechanical configuration.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principal of the invention and the manner of its implementation. The invention in its broadest and more specific forms will be further described, and defined, in each of the individual claims which conclude this specification.